The aim of this application is to establish a shared resource at Duke University centered around a confocal scanning laser microscope with a fluorescence imaging system. This facility will serve primarily to advance the light microscopy capabilities of seven biomedical research groups from several departments at the Medical School and the School of Arts and Sciences. Our group of major users represent a diverse spectrum of research interests, but common to all of us is the interest in the structure and function of cellular organelles and the use of microscopic methods. These are applied to studies of intracellular proteins, extracellular matrix components and cellular interactions in the immune system and in embryogenesis. The confocal scanning laser microscope is a new technological development which extends considerably the information yield from experiments involving light microscopy. A common theme for the projects that will employ this technology is that they previously entailed either frozen sections or immuno-EM. All of us could not obtain sufficient resolution from conventional microscopy due to the geometry of our specimens. With the optical sectioning of confocal microscopy many specific goals that we now pursue by more cumbersome methods will become more readily attainable. The image storage, analysis and reconstruction capabilities will permit facility users to utilize the full resolution of the confocal optics. We shall now be able, for the first time, to localize the various proteins in our cells of interest, do it with high precision, and follow the dynamic changes in their distributions with greater resolution and more quantitatively.